Conventionally, a plate for an electro-thermal window formed with a transparent conductive film is known (see, for example, Patent Document 1). A bus bar is formed on both ends of the transparent conductive film formed in the plate for an electro-thermal window. One bus bar is connected to a direct current power source whereas another bus bar is grounded. When the transparent conductive film is energized, the transparent conductive film generates heat, so that fog (water droplets) or the like created on the plate for the window can be removed. However, by forming the transparent conductive film, the transmission of electromagnetic waves becomes difficult. Therefore, Patent Document 1 discloses multiple openings being orderly arranged through which electromagnetic waves of a predetermined frequency can be transmitted.